JP2018172618A - Method for recycling polyamide composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recycling a polyamide composition, capable of collecting high-quality polyamide, and solving the problem that with a conventional method for collecting nylon 66 from a polyamide composition such as an air bag scrap cloth, complete removal of silicon is difficult, and the quality of collected polyamide from which silicon is removed is inferior.SOLUTION: A method for recycling a polyamide composition includes: a solution heating step of heating together with ethylene glycol at 180°C or more a polyamide composition which contains polyamide bound to or mixed with a substance insoluble in ethylene glycol stored in a net-like container 2 of a dissolving pot 3 so as to boil an ethylene glycol solution of silicon-coated polyamide, instantly dissolve silicon-coated polyamide, and separate polyamide from silicon; and a polyamide collecting step of collecting high-quality polyamide separated from the substance insoluble in ethylene glycol.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for recycling a polyamide composition, which recovers polyamide from defective products or waste products of products containing a polyamide combined or mixed with a substance insoluble in ethylene glycol.

  Conventionally, there has been known a method for recovering a polyamide from a defective product including a polyamide combined with or mixed with a substance insoluble in ethylene glycol or a waste product of the product (hereinafter referred to as “polyamide composition”). Yes.

  As this type of method, using an airbag scrap cloth coated with silicon on the airbag base fabric, the silicon coating layer is peeled and removed by immersing an alkaline solution in the airbag scrap cloth and then dehydrating it. In addition, it is possible to recover 66 nylon (see Patent Document 1) and an airbag base fabric made of polyamide fiber coated with silicon, and an alkali-isopropyl alcohol solution is applied to the airbag base fabric. There was a technique (see Patent Document 2) in which the silicone coated on the airbag base fabric was removed by dipping the nylon fabric and the nylon 66 could be recovered.

JP 2001-180413 A JP 2009-269475 A

  However, in the conventional method of recovering nylon 66, it is difficult to completely remove silicon, and there is a problem that the quality of polyamide recovered by removing silicon is inferior, and silicon is completely removed depending on the type of silicon. There was a problem that it might not be possible. Furthermore, the conventional method of recovering nylon 66 has a problem that waste liquid treatment is required because alkali is used.

  A method of recovering polyamide by dissolving polyamide in a polyamide composition such as nylon 66 in a solvent can be easily considered. However, polyamide cannot be dissolved in a generally used solvent, and the polyamide is dissolved. For this, it is necessary to use a solvent of formic acid or phenols. However, this formic acid and phenols are not only harmful, but if the solvent of formic acid or phenols is distilled off to recover the polyamide, the entire polyamide becomes a large solid and the polyamide cannot be recovered. Even if the polyamide can be recovered, there remains a problem that harmful substances such as formic acid and phenols remain in the recovered polyamide.

  In addition, a method of precipitating and precipitating polyamide by adding water or the like to a solution of a harmful solvent of formic acid or phenols and a polyamide composition is also conceivable, but the residual liquid after separating the polyamide is not limited to the above harmful solvent and water. Since it becomes a two-component system, it becomes difficult to recover the polyamide solvent, and wastewater treatment is also required. Concentrated sulfuric acid, which is a good solvent for polyamide, is not only dangerous for the human body, but if water is added to precipitate the polyamide, it will generate severe heat and may cause ignition. It did not have.

  From the above, for polyamide compositions such as airbag scrap cloth, there is currently no method for recovering high-quality polyamide from the polyamide composition and reusing the polyamide.

  The present invention has been made in view of the above problems, and a method for recycling a polyamide composition capable of recovering a high-quality polyamide from a polyamide composition containing a polyamide combined or mixed with a substance insoluble in ethylene glycol. The purpose is to provide.

  In order to solve the above problems and achieve the above object, according to the first aspect of the present invention, there is provided a polyamide composition containing a polyamide combined with or mixed with a substance insoluble in ethylene glycol together with ethylene glycol. A solution heating step for heating at a temperature of ℃ or higher to separate the polyamide and the substance insoluble in ethylene glycol, and a polyamide recovery step for recovering the polyamide separated from the substance insoluble in ethylene glycol by the solution heating step. is there.

  According to the present invention, a polyamide composition containing a polyamide combined or mixed with a substance that is insoluble in ethylene glycol is heated with ethylene glycol at a temperature of 180 ° C. or higher to bond or mix with a substance that is insoluble in ethylene glycol. The polyamide glycol solution of the prepared polyamide is boiled, and the polyamide combined with or mixed with the substance that is not soluble in ethylene glycol dissolves instantly, and the polyamide can be separated from the substance that is not soluble in ethylene glycol. It can be recovered.

  Of the present invention, the second aspect relates to a method for recycling the polyamide composition according to the first aspect, wherein the polyamide recovery step has a concentration of polyamide separated from a substance insoluble in ethylene glycol from 10%. A solution cooling step of cooling a 30% polyamide ethylene glycol solution to 130 ° C. or lower, and a non-fluid material composed of ethylene glycol and polyamide solidified by cooling in the solution cooling step is vacuum dried at 130 ° C. or lower to produce ethylene glycol And a vacuum drying recovery step of recovering the polyamide by distilling off.

  According to the present invention, by using an ethylene glycol solution of polyamide having a polyamide concentration of 10% to 30%, the amount of ethylene glycol as a solvent for the polyamide does not become excessive, and the entire ethylene glycol solution of polyamide is a sherbet. Since it is soft and solid and does not separate into two layers, it can be supplied to a vacuum dryer as it is without filtering or centrifuging, and the process can be simplified. This is a characteristic effect of the ethylene glycol solution. In addition, by cooling the ethylene glycol solution of polyamide to 130 ° C. or lower, a non-fluid composed of soft and solid ethylene glycol and polyamide can be produced, and the non-fluid composed of soft and solid ethylene glycol and polyamide at 130 ° C. or lower. High quality polyamide can be recovered by vacuum drying and distilling off ethylene glycol. The polyamide obtained by distilling off ethylene glycol in this way has almost no decrease in the degree of polymerization, and once purified by dissolving in ethylene glycol, which is a solvent for polyamide, to obtain a high-quality polyamide. Can do. The distilled ethylene glycol can be reused as a polyamide solvent when the polyamide composition recycling method is carried out. Furthermore, the ethylene glycol solution is cooled to 130 ° C. or lower, and the non-fluid consisting of soft and solid ethylene glycol and polyamide is vacuum-dried to distill off the ethylene glycol, so that ethylene glycol is not a good solvent for polyamide. The polyamide particles can be recovered in the form of small particles without fusing to form a lump.

  According to a third aspect of the present invention, there is provided a method for recycling a polyamide composition according to the first aspect, wherein the polyamide recovery step comprises removing an ethylene glycol solution of polyamide separated from a substance insoluble in ethylene glycol with a pore size. A vacuum chamber discharge step in which a nozzle plate having a hole of 0.1 mm to 1.0 mm is formed and discharged to a vacuum chamber having a vacuum inside, and ethylene in an ethylene glycol solution of polyamide discharged in the vacuum chamber discharge step A vaporization and recovery step of recovering polyamide by evaporating glycol in a vacuum chamber.

  According to the present invention, an ethylene glycol solution of polyamide separated from a substance insoluble in ethylene glycol is passed through a nozzle plate having a hole diameter of 0.1 mm to 1.0 mm, and the inside is discharged into a vacuum chamber having a vacuum. Therefore, even if ethylene glycol is vaporized in the vacuum chamber, since ethylene glycol is a poor solvent for polyamide, the polyamide falls apart without falling into a string, and the falling polyamide is placed on the bottom of the vacuum chamber. Can be deposited. The fallen matter deposited on the bottom surface of the vacuum chamber is melted due to insufficient cooling, but it is brittle and easily disassembles and can be recovered as polyamide strips. Moreover, the ethylene glycol vaporized in the vacuum chamber can be reused as a solvent for the polyamide when the polyamide composition is recycled.

According to the method for recycling a polyamide composition of the present invention, the polyamide can be reused by separating the polyamide from the conventionally disposed polyamide and the polyamide composition comprising other components.

It is a figure which shows the polyamide collection | recovery apparatus used for the recycling method of the polyamide composition in 1st Embodiment of this invention. It is a figure which shows the polyamide collection | recovery apparatus used for the recycling method of the polyamide composition in 2nd Embodiment of this invention. It is a figure which shows the polyamide collection | recovery apparatus used for the recycling method of the polyamide composition in 3rd Embodiment of this invention.

(First embodiment)
1st Embodiment of the recycling method of the polyamide composition of this invention is described. First, the polyamide recovery apparatus used in the method for recycling the polyamide composition of the present invention will be described. Here, FIG. 1 is a view showing a polyamide recovery apparatus used in the polyamide composition recycling method in the first embodiment of the present invention.

  As shown in FIG. 1, the polyamide recovery apparatus 1 includes a net-like container 2, a melting pot 3, a reflux condenser 4, and a cooling tank 5.

  The net-like container 2 is a container having a wire diameter of 2 mm and formed from a wire mesh of 5 mesh (5 meshes per inch), into which air-bag waste that has been shredded is placed. In the present embodiment, the net-like container 2 is used. However, the present invention is not limited to this, and a punching plate, a lattice box having a lattice shape, or the like may be used.

  The melting pot 3 is a pot made of stainless steel (SAS316 or the like) as a material, and the net-shaped container 2 is suspended inside, and the lower surface of the suspended net-shaped container 2 is in contact with and supported by the inner bottom portion.

  The reflux condenser 4 is formed integrally with the melting pot 3 via a pipe at the upper right of the melting pot 3. The reflux condenser 4 is a reflux condenser, and is a device for condensing the solvent that has been boiled into a gas and condensing it into a liquid, and returning the liquid solvent to the melting pot 3.

  The cooling tank 5 is a container for storing the liquid sent from the melting pot 3 via the on-off valve 6 and allowing the liquid to cool. Specifically, the liquid stored in the melting pot 3 is sent to the cooling tank 5 when the on-off valve 6 is opened.

  Next, the method for recycling the polyamide composition in the first embodiment of the present invention will be specifically described. This embodiment demonstrates the case where polyamide is collect | recovered from the airbag wastes containing the silicon-coated polyamide. Here, the air bag waste is a defective product generated in the manufacturing process of the air bag, a waste product of the air bag recovered from the scrapped vehicle, or the like. In this embodiment, the air bag waste containing the silicon-coated polyamide is used as the polyamide composition containing the polyamide combined with or mixed with the substance that is not soluble in ethylene glycol. Bonded or mixed with materials that are insoluble in ethylene glycol, such as nylon carpets using a glass fiber base fabric, nylon nonwoven fabrics backed with styrene butadiene rubber (SBR), or nylon wool blended yarns in which nylon and wool are mixed Any polyamide composition containing the prepared polyamide may be used (the same applies to other embodiments and examples).

  First, airbag waste is shredded to an appropriate size (polyamide composition shredding step). The shredding size is preferably about 2 cm to 10 cm in length on one side, but since it varies depending on the equipment used and the amount of processing, the shredding size of airbag debris is not particularly limited. The shredding size of the air bag waste may be any size as long as the silicon coat contained in the air bag waste is separated by the net-like container 2 and the silicon film piece becomes a residue in the net-like container 2. That is, when the shredded airbag waste is put in the net-like container 2 and the polyamide contained in the shredded airbag waste is dissolved, the silicon film piece that becomes a residue does not pass through the net-like container 2. That's fine.

  Next, the airbag waste shredded in the polyamide composition shredding step is put into the net-like container 2, the melting pot lid 3 a of the melting pot 3 is opened, and the reflux condenser 4 is integrally formed. 3 (dissolution pot insertion process). Specifically, the melting pot 3a of the melting pot 3 is opened, and the net-shaped container 2 containing airbag waste is hung on the hook in the melting pot lid 3a, and the net-shaped container 2 is inserted. In this way, the shredded airbag waste in the net-like container 2 is suspended in the melting pot 3 (see FIG. 1).

  Next, ethylene glycol is injected from the upper part of the melting pot 3 with the melting pot 3a of the melting pot 3 opened (ethylene glycol injection step). Here, when ethylene glycol is injected into the melting pot 3, the on-off valve 6 at the bottom of the melting pot 3 is closed, so that the injected ethylene glycol accumulates in the melting pot 3. . Here, the amount of ethylene glycol injected into the dissolution vessel 3 is determined after the dissolution vessel 3 is heated by a heating burner (not shown) and the polyamide is heated and dissolved in the injected ethylene glycol, as will be described later. Ethylene glycol is injected so that the concentration of polyamide in the ethylene glycol solution is 10% to 30%. That is, a little more ethylene glycol is injected, and the polyamide is heated and dissolved in the injected ethylene glycol so that the concentration of the polyamide in the ethylene glycol solution after evaporation of the ethylene glycol is 10% to 30%. Good. Here, “the concentration of the polyamide in the ethylene glycol solution is 10% to 30%” means that the concentration of the polyamide in the ethylene glycol solution of the polyamide is 10% to 30%, and the concentration of the polyamide is smaller than 10%. In this case, since the injection amount of ethylene glycol as a solvent is large, even if the temperature of the polyamide ethylene glycol solution is lowered to 130 ° C. or lower, it becomes a slurry, so it is necessary to vacuum dry after further filtration or centrifugation, The number of filtration or centrifugation steps increases and the process becomes complicated, and a large amount of the ethylene glycol solvent must be removed, resulting in wasted production efficiency and energy. In addition, when the amount of injected ethylene glycol is reduced and the polyamide concentration is higher than 30%, the polyamide composition is poorly immersed and the polyamide is not sufficiently extracted. Polyamide adheres to the silicon film piece adhering to the net-like container 2 and the polyamide recovery rate deteriorates. On the other hand, when the concentration of polyamide is 10% to 30%, when the temperature of the polyamide ethylene glycol solution is lowered to 130 ° C. or lower, the entire polyamide ethylene glycol solution is soft and hardened and does not separate into two layers. Therefore, it can be directly put into a vacuum dryer thereafter, and the process can be simplified.

  Next, the melting pot lid 3a of the melting pot 3 is closed, and the melting pot 3 is heated at a temperature of 180 ° C. or higher by a heating burner (not shown). More specifically, the air bag waste containing the chopped silicon-coated polyamide contained in the melting pot 3 is heated with ethylene glycol at a temperature of 180 ° C. or more (solution heating step). As described above, when the ethylene glycol solution of the polyamide coated with silicon is boiled by heating the melting pot 3 with a heating burner (not shown), the polyamide coated with silicon is instantaneously dissolved and the polyamide is separated from silicon. It will be. Thus, since the polyamide is instantaneously separated from silicon when the silicon-coated polyamide ethylene glycol solution is boiled, the dissolution time of the polyamide by heating the dissolution vessel 3 is effectively the temperature increase time of the dissolution vessel 3. . Further, a solution heating step is performed, and the ethylene glycol of the polyamide ethylene glycol solution that has become gas is condensed and liquefied by the reflux condenser 4, and the ethylene glycol that has become the liquid is returned to the melting pot 3. In the present embodiment, the melting pot 3 is heated using a heating burner (not shown). However, the present invention is not limited to this, and the melting pot 3 may be heated by other heating methods such as heating with a heating medium. .

  Next, an ethylene glycol solution of polyamide in which the concentration of the polyamide separated from silicon in the melting pot 3 is 10% to 30% is withdrawn into the cooling tank 5 by opening the on-off valve 6 at the lower part of the melting pot 3. 5 to cool to 130 ° C. or lower (solution cooling step). When the polyamide ethylene glycol solution is extracted into the cooling bath 5, the polyamide ethylene glycol solution may be filtered again and extracted into the cooling bath 5. Thus, the polyamide ethylene glycol solution is filtered again and extracted into the cooling bath 5, whereby a polyamide ethylene glycol solution from which silicon is further removed can be obtained. Further, since silicon which has been coated with polyamide in silicon is left as a residue on the net-like container 2 in the melting pot 3 in a state of being individually wound as a silicon film piece, the net-like container 2 is pulled up and the melting pot 3 is pulled up. Take out from. The polyamide adhering to the residue of the silicon film piece can be recovered by a method such as adding it to the next batch separately. Then, the polyamide ethylene glycol solution in the cooling bath 5 is allowed to cool and cooled, and when cooled to 130 ° C., the polyamide ethylene glycol solution starts to solidify. The non-fluid material composed of the solidified ethylene glycol and polyamide is in a state where a sherbet-like material is soft and hardened.

  Next, a non-fluid material composed of ethylene glycol and polyamide in which a sherbet-like material is soft and hardened is put into a vacuum dryer (not shown) and dried in vacuum, and the polyamide is recovered by distilling off ethylene glycol (vacuum) Dry recovery process). Here, the vacuum dryer may be any vacuum dryer such as a drum-type vacuum dryer, a tumbler-type vacuum dryer, a belt conveyor-type vacuum dryer, a shelf-type vacuum dryer, etc., but ethylene glycol When a vacuum dryer provided with a solvent recovery device is used for recovering the solvent, the polyamide can be easily recovered from the non-fluid composed of ethylene glycol and polyamide. Moreover, when vacuum-drying the non-fluid consisting of ethylene glycol and polyamide, a step of stirring the non-fluid consisting of ethylene glycol and polyamide using a stirring device (non-fluid stirring step) may be provided. In this way, by performing the non-fluid stirring step, the non-fluid consisting of ethylene glycol and polyamide can be stirred and the ethylene glycol can be easily distilled off. And the drying temperature of the non-fluid which consists of ethylene glycol and polyamide by a vacuum dryer is 130 degrees C or less (desirably 100 degrees C or less). This “drying temperature is 130 ° C. or lower” means that the polyamide is more likely to deteriorate when the drying temperature is higher. However, when the drying temperature is 130 ° C. or higher, the polyamide particles are fused and hardened. Because it will end up. In addition, when the vacuum dryer is evacuated, the boiling point is lowered, but the degree of vacuum in the vacuum dryer is such that the drying temperature is the boiling point of ethylene glycol. Thus, by using a vacuum dryer to distill off ethylene glycol, a granular polyamide can be obtained. The obtained granular polyamide can be used as a raw material as it is, but it is easier to use the granular polyamide after melting and pelletizing it. In addition, the granular polyamide obtained in this manner has almost no decrease in the degree of polymerization, and once purified by dissolving in ethylene glycol as a solvent, a high quality polyamide can be obtained. In the present embodiment, the vacuum drying recovery process and the non-fluid stirring process have been described as separate processes. However, these processes are not separate processes, and vacuum drying and non-fluid stirring are performed with a single machine. It is good also as a dry stirring collection process.

  In the present embodiment, an ethylene glycol solution of polyamide having a polyamide concentration of 10% to 30% separated from silicon in the melting pot 3 is withdrawn into the cooling tank 5 by opening the on-off valve 6 at the bottom of the melting pot 3. A solution cooling step of cooling by cooling to 130 ° C. or lower in the cooling bath 5 and a non-fluid material composed of ethylene glycol and polyamide in which a sherbet-like material is soft and hardened is put into a vacuum dryer (not shown) and vacuum-dried. Although the vacuum drying recovery process for recovering the polyamide by distilling off ethylene glycol is a separate process, the process is not limited to this, and these processes may not be separate processes and may be a single polyamide recovery process. Here, the polyamide recovery step is a step of recovering the polyamide separated from the silicon by the solution heating step. If the polyamide recovery step is described in more detail, the polyamide in the ethylene glycol solution of the polyamide separated from the silicon in the dissolution vessel 3 will be described. A polyamide ethylene glycol solution with a concentration of 10% to 30% is drawn out into the cooling bath 5 and cooled, and a non-fluid material composed of ethylene glycol and polyamide in which a sherbet-like material is soft and hardened is put into a vacuum dryer and vacuum dried. And recovering polyamide by distilling off ethylene glycol.

  As described above, according to the present embodiment, the use of an ethylene glycol solution of polyamide having a polyamide concentration of 10% to 30% prevents the amount of ethylene glycol, which is a polyamide solvent, from being excessive, and the polyamide. Since the entire ethylene glycol solution is soft and solid like a sherbet and does not separate into two layers, it can be supplied to a vacuum dryer as it is without filtration or centrifugation, and the process can be simplified. This is a characteristic effect of the ethylene glycol solution. Further, by cooling the ethylene glycol solution of polyamide to 130 ° C. or less, a non-fluid composed of soft and solid ethylene glycol and polyamide can be produced, and the non-fluid composed of soft and solid ethylene glycol and polyamide is vacuum-dried to produce ethylene. It is possible to recover high-quality polyamide by distilling off the glycol. The polyamide obtained by distilling off ethylene glycol in this way has almost no decrease in the degree of polymerization, and once purified by dissolving in ethylene glycol, which is a solvent for polyamide, to obtain a high-quality polyamide. Can do. The distilled ethylene glycol can be reused as a polyamide solvent when the polyamide composition recycling method is carried out. Furthermore, the ethylene glycol solution is cooled to 130 ° C. or lower, and the non-fluid consisting of soft and solid ethylene glycol and polyamide is vacuum-dried to distill off the ethylene glycol, so that ethylene glycol is not a good solvent for polyamide. The polyamide particles can be recovered in the form of small particles without fusing to form a lump. As a result, it is possible to obtain a regenerated polyamide that can be used as a raw material for producing polyamide yarn, which has been said to be difficult for recycled products, and can be used in the same manner as the polyamide that is a virgin raw material.

(Second Embodiment)
Next, a second embodiment of the method for recycling the polyamide composition of the present invention will be described.

  The main difference between the second embodiment and the first embodiment of the present invention is that, in the first embodiment, an ethylene glycol solution of polyamide is sent to the cooling tank 5 and the sent ethylene glycol solution of polyamide is cooled in the cooling tank. 5 was cooled to a non-fluid consisting of ethylene glycol and polyamide, and high-purity polyamide was recovered from the non-fluid consisting of ethylene glycol and polyamide using a vacuum dryer. In the second embodiment, the ethylene glycol solution of polyamide is sent to the supply tank 12, and the sent ethylene glycol solution of polyamide is discharged from the filtration tank 13 to the vacuum tank 14 in the form of rain in May to vaporize the ethylene glycol, thereby purifying the purity. The place where high polyamide is recovered is different. Note that the second embodiment will be described with a focus on differences from the first embodiment. Moreover, in 2nd Embodiment, about the same structure as 1st Embodiment, the same code | symbol is used and the same effect is demonstrated and description is abbreviate | omitted.

  Conventionally, a spray dryer method is known as a method of spraying a solution in a mist and applying hot air thereto to evaporate a solvent to separate a solute from the solution. Using this spray dryer method, even if the ethylene glycol solution of polyamide from which silicon has been separated and removed is sprayed in a vacuum to evaporate the ethylene glycol, the polymer solution is a viscous liquid like a chickenpox and is sprayed. In this embodiment, the following method for recycling the polyamide composition was used without using the spray dryer method. Specific contents of the method will be described later.

  First, a polyamide recovery apparatus used in the polyamide composition recycling method of the second embodiment of the present invention will be described. Here, FIG. 2 is a figure which shows the polyamide collection | recovery apparatus used for the recycling method of the polyamide composition in 2nd Embodiment of this invention. In FIG. 2, the components up to the on-off valve 6 in FIG. 1 are omitted, and a supply tank 12 is provided below the on-off valve 6 via a pipe.

  The polyamide recovery apparatus 11 used in the method for recycling the polyamide composition in the present embodiment includes a net-like container 2, a melting pot 3, a reflux condenser 4, a supply tank 12, a filtration tank 13, and a vacuum tank 14. , A flux condenser 15, a recovery tank 16, and a vacuum pump 17. As described above, the net-like container 2, the melting pot 3, and the reflux condenser 4 are the same as those in the first embodiment.

  The supply tank 12 is a container for storing the liquid sent from the melting pot 3 via the on-off valve 6 and supplying the sent liquid to the filtration tank 13. Here, a gear pump 18 is provided in a pipe on the downstream side of the supply tank 12, and the gear pump 18 sends liquid from the supply tank 12 to the filtration tank 13 while being quantified at a predetermined speed.

The filter tank 13 filters the liquid supplied from the supply tank 12, and is filled with 200 mesh Morundum sand, which is a filter medium mainly composed of alumina, with a thickness of 50 mm. The filtration tank 13 is detachably fixed to the vacuum tank 14 with bolts. And if the pressure in the filtration tank 13 will be 20 kg / cm < ² > or more, a filter medium (200 mesh Morundum sand) will be replaced | exchanged. A nozzle plate 19 having a diameter of 40 cm is provided at the lowermost part of the filtration tank 13. The nozzle plate 19 has 4000 holes having a diameter (nozzle diameter) of 0.3 mm. This nozzle plate 19 is detachably fixed to the filtration tank 13. When the filtration tank 13 is washed, the nozzle plate 19 is removed from the filtration tank 13, and the clogging of the nozzle plate 19 can be removed by washing or incineration with a solvent. In this embodiment, the diameter of the hole formed in the nozzle plate 19 is 0.3 mm. However, the diameter is not limited to this, but is 0.1 to 1.0 mm (preferably 0.3 to 0.6 mm). It is good. This "the diameter of the hole in the nozzle plate 19 (nozzle diameter) is 0.1 mm to 1.0 mm" means that when the nozzle diameter is 0.1 mm or less, the polyamide ethylene glycol solution is a viscous liquid. Therefore, there is a high possibility that the holes in the nozzle plate 19 will be clogged immediately, and when the nozzle diameter is 1.0 mm or more, the flow of the polyamide ethylene glycol solution becomes non-uniform, resulting in a large lump in the vacuum chamber 14. Will be released. Thus, the ethylene glycol solution of polyamide released into the vacuum chamber 14 has a large lump portion, and the ethylene glycol is insufficiently vaporized to cause fusion and block, and the inside of the vacuum chamber 14 contains ethylene glycol. Will remain. In the present embodiment, the number of holes formed in the nozzle plate 19 is 4000. However, the number of holes is not limited to this, and the number of holes in the nozzle plate 19 can be freely determined by processing capacity (production capacity). Furthermore, in the present embodiment, the filter medium 13 is filled with Morundum sand filter medium, but the present invention is not limited thereto, and the filter tank 13 may be filled with metal sand filter medium.

  The vacuum chamber 14 is set by the vacuum pump 17 so that the inside has a predetermined degree of vacuum. The side wall of the vacuum chamber 14 is formed with a double structure consisting of an inner layer and an outer layer, and the inner layer has a punching plate structure with holes having a diameter of 3 mm. Then, the ethylene glycol vaporized in the vacuum chamber 14 is sent to the flux capacitor 15 through the space between the inner layer and the outer layer of the vacuum chamber 14.

  The flux condenser 15 is provided in the vacuum chamber 14 via piping. This reflux condenser 15 is an apparatus for condensing the solvent that has been boiled into gas by condensing it into a liquid, and collecting the solvent that has become liquid in the recovery tank 16, as with the reflux condenser 4 of the first embodiment. It is.

  Next, a method for recycling the polyamide composition in the second embodiment of the present invention will be specifically described. In addition, since it is the same as that of 1st Embodiment from a polyamide composition shredding process to a solution heating process, description is abbreviate | omitted, and this embodiment demonstrates from the process following a solution heating process. That is, when the melting pot 3 is heated, the silicon-coated polyamide ethylene glycol solution is boiled. → The process up to the point where the polyamide is separated from the silicon by dissolving the polyamide is the same as in the first embodiment, and the description is omitted. To do. Here, in the method of recycling the polyamide composition of the second embodiment, the polyamide ethylene glycol solution is solidified when the temperature falls below 130 ° C., so that the filtration tank 13 remains while the polyamide ethylene glycol solution is in a liquid state of 130 ° C. or higher. This is a method in which an ethylene glycol solution of polyamide is discharged into the vacuum chamber 14 through the pores of the lower nozzle plate 19 in the form of May rain, and the polyamide is recovered by vaporizing ethylene glycol. This will be described in detail below.

  As described above, the method for recycling the polyamide composition in the second embodiment is the same as the method for recycling the polyamide composition in the first embodiment up to the solution heating step. When the solution heating step is completed, the following steps are performed. Is done.

  After the solution heating step is performed, the polyamide glycol solution in the melting vessel 3 having a concentration of 10% to 30% and a polyamide ethylene glycol solution at 150 ° C. or higher is opened, and the on-off valve 6 at the lower portion of the melting vessel 3 is opened. The ethylene glycol solution of polyamide is sent out to the supply tank 12 without cooling (supply tank sending step). The polyamide ethylene glycol solution is controlled at 150 ° C. in the supply tank 12. In the present embodiment, the polyamide ethylene glycol solution is controlled to 150 ° C. in the supply tank 12, but not limited to this, as long as the polyamide ethylene glycol solution does not become less than 130 ° C. in the supply tank 12. Well, it is not always necessary to control at 150 ° C.

  Next, the polyamide ethylene glycol solution sent to the supply tank 12 is sent to the filtration tank 13, and the polyamide ethylene glycol solution is filtered in the filtration tank 13 (solution filtration step). Specifically, the ethylene glycol solution of polyamide is sent from the supply tank 12 to the filtration tank 13 by the gear pump 18 while being quantified (for example, 392 cc / rotation) at a predetermined speed (for example, rotation speed 30 rpm). In this way, the amount of polyamide ethylene glycol solution sent to the filtration tank 13 by the gear pump 18 is measured and sent to the filtration tank 13 while being quantified at a predetermined speed while applying pressure. Can be passed. The polyamide ethylene glycol solution sent to the filter tank 13 is filtered by a 200 mesh Morundum sand which is a filter medium mainly composed of alumina inside the filter tank 13. Thus, by filtering the polyamide ethylene glycol solution, the filtered polyamide ethylene glycol solution easily passes through the holes of the nozzle plate 19 in which 4000 holes having a diameter of 0.3 mm are formed.

  Next, the polyamide ethylene glycol solution filtered by the filter medium is sent to the nozzle plate 19 at the bottom of the filtration tank 13 and discharged from the hole of 0.3 mm diameter of the nozzle plate 19 into the vacuum tank 14 having a vacuum inside in the form of May rain. (Vacuum chamber discharge step).

  Next, the ethylene glycol of the polyamide ethylene glycol solution released into the vacuum chamber 14 is vaporized in the vacuum chamber 14 to recover the polyamide (vaporization and recovery step). Here, at the timing when the ethylene glycol solution of polyamide is discharged from the filtration tank 13 to the vacuum tank 14, the vacuum tank 14 is evacuated by the vacuum pump 17. The degree of vacuum in the vacuum chamber 14 is sufficient if the degree of vacuum is such that ethylene glycol is vaporized at the discharge temperature of the polyamide ethylene glycol solution released into the vacuum chamber 14. Since the release temperature of the polyamide ethylene glycol solution is 130 ° C. or higher, it can be said that there is no problem even if the degree of vacuum in the vacuum chamber 14 is set low to some extent. In this embodiment, since the degree of vacuum in the vacuum chamber 14 is low, it is not necessary to strictly seal the filtration tank 13 and the vacuum tank 14 above the nozzle plate 19. Thus, when the ethylene glycol solution of polyamide is released from the hole having a diameter of 0.3 mm of the nozzle plate 19, ethylene glycol is a poor solvent for polyamide, so even if ethylene glycol is vaporized in the vacuum chamber 14, The polyamide falls apart without falling into a thread form, and the falling polyamide can be deposited on the bottom surface of the vacuum chamber 14. The fallen matter deposited on the bottom surface of the vacuum chamber 14 is melted due to insufficient cooling, but it is brittle and easily falls apart and can be collected as polyamide strips. And although the regenerated polyamide obtained from the polyamide pieces recovered in this way can be used as it is, it is more convenient to melt and pelletize it.

  The ethylene glycol vaporized in the vacuum chamber 14 is condensed by the reflux condenser 15 to become liquefied ethylene glycol, and is stored in the recovery tank 16. The ethylene glycol accommodated in the recovery tank 16 can be taken out of the recovery tank 16 by opening the recovery tank valve 16a and reused as a polyamide solvent when the polyamide composition is recycled. it can.

  According to the method for recycling the polyamide composition in the present embodiment, it is not necessary to perform the solution cooling step (see the first embodiment), so that the time until the polyamide is recovered can be shortened and the energy efficiency is also good. . In addition, since it is not necessary to carry out the vacuum drying recovery process (see the first embodiment), it is possible to omit the trouble of putting it in the vacuum dryer.

  In the present embodiment, the polyamide ethylene glycol solution in the dissolution vessel 3 is fed to the supply tank 12, and the polyamide ethylene glycol solution fed to the supply tank 12 is sent to the filtration tank 13, where the filtration tank 13 is a solution filtration step in which the polyamide ethylene glycol solution is filtered, and the polyamide ethylene glycol solution filtered by the filter medium is sent to the nozzle plate 19 at the lower part of the filtration tank 13, and from the hole having a diameter of 0.3 mm in the nozzle plate 19. A vacuum chamber discharging step in which the inside is discharged into a vacuum chamber 14 and a vaporization recovery step in which the ethylene glycol of the polyamide ethylene glycol solution released in the vacuum chamber 14 is vaporized in the vacuum chamber 14 to recover the polyamide. However, the present invention is not limited to this, and these steps are not considered as separate steps. It may be. Here, the polyamide recovery step is a step of recovering the polyamide separated from the silicon by the solution heating step. When the polyamide recovery step is described in a little more detail, the polyamide ethylene glycol solution fed to the supply tank 12 is filtered by the filtration tank 13. In this process, the ethylene glycol solution of the filtered polyamide is discharged from a 0.3 mm diameter hole in the nozzle plate 19 at the bottom of the filter tank 13 into a vacuum tank 14 having a vacuum inside and collected as a polyamide strip. .

  As described above, according to the present embodiment, the ethylene glycol solution of polyamide separated from silicon is passed through the nozzle plate 19 in which holes having a hole diameter of 0.3 mm are formed, and the inside is discharged into the vacuum chamber 14 having a vacuum. As a result, even if ethylene glycol is vaporized in the vacuum chamber 14, since the ethylene glycol is a poor solvent for polyamide, the polyamide falls apart without falling into a string, and the falling polyamide is removed from the vacuum chamber 14. It can be deposited on the bottom. And the fallen matter deposited on the bottom surface of the vacuum chamber 14 is brittle because it is not sufficiently cooled, and easily falls apart and can be recovered as polyamide strips. Further, the ethylene glycol vaporized in the vacuum chamber 14 can be reused as a polyamide solvent when the polyamide composition is recycled.

(Third embodiment)
Next, a third embodiment of the method for recycling the polyamide composition of the present invention will be described.

  The main difference between the third embodiment and the first embodiment of the present invention is that in the first embodiment, ethylene glycol (solvent), which is a gas obtained by boiling an ethylene glycol solution of polyamide, is condensed by a reflux condenser 4. In contrast, in the third embodiment of the present invention, an ethylene glycol solution of polyamide is used to store liquid ethylene glycol (solvent) in the cooling tank 5 via the dissolution vessel 3. The boiling ethylene glycol (solvent) is condensed by the solvent recovery condenser 21 to be liquid, and the liquid ethylene glycol (solvent) is recovered by the solvent recovery tank 22. Here, the reflux condenser 4 and the solvent recovery condenser 21 can be switched by condenser switching sections 23a and 23b. Note that the third embodiment will be described with a focus on differences from the first embodiment. Moreover, in 3rd Embodiment, about the same structure as 1st Embodiment, the same code | symbol is used and the same effect is demonstrated and description is abbreviate | omitted.

  The condenser 21 for solvent recovery condenses ethylene glycol, which is a solvent obtained by boiling an ethylene glycol solution of polyamide into a liquid, and makes the solvent recovery tank 22 recover the ethylene glycol (solvent) that has become the liquid. It is a device for. The solvent recovery tank 22 is a container for recovering the ethylene glycol (solvent) of the polyamide ethylene glycol solution made liquid by the solvent recovery condenser 21. The condenser switching units 23 a and 23 b are constituted by switching valves for switching between the reflux condenser 4 and the solvent recovery condenser 21. In the present embodiment, the capacitor switching units 23a and 23b are configured by switching valves. However, the present invention is not limited to this, and may be a capacitor switching unit other than the switching valve.

  Next, the method for recycling the polyamide composition in the third embodiment of the present invention will be specifically described. Here, in the third embodiment, a little more ethylene glycol is injected in the ethylene glycol injection process, and the ethylene glycol solution in the dissolution vessel 3 after boiling the polyamide glycol solution by heating the dissolution vessel 3 is heated. This is an embodiment for reducing the concentration of the polyamide from 10% to 30%. In addition, about 3rd Embodiment, since it is the same as that of 1st Embodiment except the above, description is abbreviate | omitted and demonstrates the different process after a solution heating process.

  When the solution heating step is performed, the ethylene glycol of the polyamide ethylene glycol solution that has become a gas is condensed and liquefied by the reflux condenser 4, and the ethylene glycol that has become the liquid is returned to the melting pot 3. Then, the flow path of the reflux condenser 4 and the solvent recovery condenser 21 is switched by closing the condenser switching section 23a and opening the condenser switching section 23b (condenser flow path switching step). As a result, the flow path from the dissolution vessel 3 to the solvent recovery condenser 21 through the pipe passes, and the ethylene glycol solution of the polyamide in the dissolution vessel 3 boils into a gas and is condensed in the solvent recovery condenser 21 to form a liquid. The ethylene glycol that has become the liquid is recovered in the solvent recovery tank 22. Then, the ethylene glycol recovered in the solvent recovery tank 22 is taken out of the solvent recovery tank 22 by opening the recovery tank valve 22a, and reused as a polyamide solvent when the polyamide composition recycling method is carried out. Can do. In the present embodiment, it has been described that after the ethylene glycol that has been gasified is liquefied by the reflux condenser 4, the condenser switching units 23a and 23b are switched and liquefied by the solvent recovery condenser 21. Not limited to this, after liquefying with the solvent recovery condenser 21, the condenser switching units 23 a and 23 b may be switched and liquefied with the reflux condenser 4. You may mutually perform liquefaction in the flux capacitor | condenser 4. FIG.

  According to this embodiment, even when a little more ethylene glycol is injected in the ethylene glycol injection step, the ethylene glycol returned to the dissolution vessel 3 can be adjusted, and the polyamide concentration of the ethylene glycol solution in the dissolution vessel 3 is 10%. To 30%.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

(Experimental example of the first embodiment)
Hereinafter, an experimental example of the first embodiment of the present invention will be described.

  Compared with “when the concentration of the polyamide in the ethylene glycol solution is lower than 10% or higher than 30%”, this experimental example is “when the concentration of the polyamide in the ethylene glycol solution is increased from 10% to 30%”. "" Is an experimental example showing that good results can be obtained.

  As the polyamide composition used in this experimental example, airbag scrap (polyamide composition) containing silicon-coated polyamide consisting of 85% nylon 66 and 15% silicon was used. This air bag waste is shredded to about 5 cm × 10 cm, and using the shredded air bag waste, the melting pot insertion process → ethylene glycol injection process → solution heating process → solution cooling process → vacuum drying recovery process A fluid stirring step was performed. Hereinafter, processes that need to be described in the above process will be described.

  In the solution heating step in this experimental example, all of the ethylene glycol vapor generated from the air bag waste containing the silicon-coated polyamide was condensed by the reflux condenser 4 and allowed to flow down to the melting pot 3. Then, when the melted kettle 3 was heated for about 1 hour and the silicon-coated polyamide ethylene glycol solution started to boil, the nylon 66 was instantaneously dissolved, and the silicon was individually wound around the wire net of the net-like container 2. It became a film and remained.

  By carrying out the solution cooling step in this example, the non-fluid mass consisting of ethylene glycol and polyamide which solidified was a collection of polymer particles and became a soft sherbet-like object. As described above, the non-fluid mass comprising solidified ethylene glycol and polyamide is not a solid mass formed by solidifying the polymer in which nylon 66 is melted.

  In the vacuum drying recovery step / non-fluid stirring step in this example, the non-fluid consisting of ethylene glycol and polyamide is taken out and put into a solvent recovery type cylindrical vacuum dryer equipped with a stirrer. The resulting non-fluid was vacuum dried with stirring (vacuum drying stirring recovery step). As described above, a non-fluid consisting of ethylene glycol and polyamide was decompressed to about 1330 Pa while stirring, and ethylene glycol was distilled off at a temperature of 95 ° C., whereby fruity nylon 66 could be obtained.

  In order to examine the quality of nylon 66 obtained by carrying out the above steps, “spinnability test” and “RV measurement” with concentrated sulfuric acid were performed. Here, for the “RV measurement”, 1 g of polyamide is put into concentrated sulfuric acid having a mass percent concentration of 96% to make 100 cc, and the viscosity of the solution at 25 ° C. is several times the viscosity of concentrated sulfuric acid having a mass percent concentration of 96%. It was measured whether it becomes.

  In the “spinnability test”, a nozzle having a hole with a hole diameter of 0.6 mm is attached to the bottom of a heating cylinder with a diameter of 30 mm, and about 50 g of nylon 66 obtained by carrying out the above-mentioned process is inserted into the heating cylinder. After that, the air in the heating cylinder in which the nylon 66 is inserted is replaced with nitrogen, the temperature is raised to 280 ° C., and the nylon 66 in the heating cylinder is pressurized with a piston to flow down the molten nylon 66 from the nozzle. . And the quality of nylon 66 was judged by whether the thread-like nylon 66 extruded from this nozzle was wound up at 200 m / min.

By changing the amount of ethylene glycol added to nylon 66, the concentration of nylon 66 in the ethylene glycol solution was 10% (Experimental Example 1), 20% (Experimental Example 2), 30% (Experimental Example 3), 5% ( Experimental Example 4), Spinnability test was performed as 35% (Experimental Example 5). The results are shown in Table 1. Here, the “ethylene glycol addition amount” is a weight ratio of the addition weight of ethylene glycol to the weight of the air bag waste, and the “primary nylon 66 recovery rate” is left as a residue on the net-like container 2. This is the recovery rate of nylon 66 when the nylon 66 adhering to the silicon film piece is not recovered.

  As can be seen from Table 1, when the concentration of nylon 66 in the ethylene glycol solution was 10%, 20%, and 30%, the primary nylon 66 recovery was high and the spinning test was good. On the other hand, when the concentration of nylon 66 in the ethylene glycol solution was 5% or 35%, the recovery rate of primary nylon 66 was low, and the spinning test was not good.

(Experimental example 6)
Experimental Example 6 is an experimental example showing that it is necessary to cool the polyamide ethylene glycol solution to 130 ° C. or lower in the solution cooling step. In this experimental example, nylon 66 was extracted from airbag waste with the same composition as in experimental example 2, and a solution heating step was performed to collect a portion of the polyamide ethylene glycol solution from which silicon was removed. The polyamide ethylene glycol solution was transferred to the flask without performing the solution cooling step, and the ethylene glycol solution was boiled off. As a result, the nylon was hardened and could not be removed.

(Experimental example 7)
Experimental Example 7 is an experimental example showing that polyamide particles are fused and solidified when the drying temperature reaches 130 ° C. or higher in the vacuum drying recovery process. In Example 1, when the drying conditions of the vacuum dryer were about 3600 Pa and 140 ° C. and ethylene glycol was distilled off, the nylon 66 particles were fused and became solid.

(Experimental example 8)
Experimental Example 8 is an experiment for comparing the quality of “before performing the above process” and “after performing the above process” with respect to “polyamide recovered from a polyamide composition containing a polyamide not coated with silicon”. It is an example. In this experimental example, “polyamide recovered from a polyamide composition containing a polyamide not coated with silicon” was subjected to the same process as in Examples 1 to 3, and the RV measurement value of concentrated sulfuric acid was measured. The quality was judged by comparison. That is, the relative viscosity of concentrated sulfuric acid was measured. Specifically, in Experimental Example 8, the same process as in Examples 1 to 3 was performed on non-silicon-coated airbag waste (polyamide compound) using a nylon 66 woven fabric, and concentrated sulfuric acid was used. RV measurement was performed. As a result, when the RV measurement values of concentrated sulfuric acid of “polyamide of airbag waste before carrying out the above process” and “polyamide recovered after carrying out the above process” were compared, The RV measurement value of concentrated sulfuric acid of “polyamide of air bag waste” and the RV measurement value of concentrated sulfuric acid of “polyamide recovered after carrying out the above steps” were both 3.4. From this, it was found that the “polyamide recovered by carrying out the treatment in the above-mentioned process” has almost no decrease in the degree of polymerization. The RV measurement value of this concentrated sulfuric acid is almost the same value as that of commercially available virgin nylon 66 resin, and it can be spun in the “spinning test” while being recycled nylon 66, so that it is a good quality recycled product. I can say that.

(Example of the second embodiment)
Next, examples of the second embodiment of the present invention will be described.
(Experimental example 9)
In Experimental Example 9, the solution filtration step → vacuum tank discharge step → vaporization recovery step was performed using an ethylene glycol solution of nylon 66 (the concentration of nylon 66 is 20%) sent from the dissolution vessel 3 to the supply tank 12. . Here, the ethylene glycol solution of nylon 66 sent out to the supply tank 12 is controlled to 150 ° C. in the supply tank 12.

  In the solution filtration step in this experimental example, the ethylene glycol solution of nylon 66 is quantified (for example, 392 cc / revolution) from the supply tank 12 to the filtration tank 13 at a predetermined speed (for example, 392 cc / revolution) using a 392 cc gear pump 18. Will be sent.

  In the vacuum chamber discharge step in this example, the ethylene glycol solution of nylon 66 was set to a vacuum degree of about 3330 Pa by the vacuum pump 17 through the nozzle plate 19 having a hole diameter of 0.3 mm at the bottom of the filtration tank 13. It is discharged into the vacuum chamber 14 in the form of May rain.

  As a result of performing RV measurement on the nylon 66 recovered in this example, the RV measurement value was 3.4. Moreover, when this was remelted and pelletized, the spinning test described above was performed, and as a result, spinning was obtained. From this, the recovered nylon 66 had a good quality result.

(Experimental example 10)
In Experimental Example 10, “the diameter of the hole formed in the nozzle plate 19 is 0.1 mm to 1.0 mm” as compared with “the diameter of the hole formed in the nozzle plate 19 is 1.0 mm or more”. It is an experimental example which shows that it is a favorable result. In this experimental example, a nozzle plate 19 having a hole diameter of 1.2 mm was used. In Experimental Example 10, the nozzle plate 19 having a diameter (nozzle diameter of 1.2 mm) is used, but the others are the same as in Experimental Example 9. Then, an ethylene glycol solution of nylon 66 was discharged into the vacuum chamber 14 using a nozzle plate 19 having a nozzle diameter of 1.2 mm. As a result, the ethylene glycol solution of nylon 66 dropped from the nozzle plate 19 into the vacuum chamber 14 and overlapped, and the nylon 66 was solidified by fusing. For this reason, at least the nozzle plate 19 having a hole diameter of 1.2 mm has a non-uniform flow of the polyamide ethylene glycol solution and is discharged into the vacuum chamber 14 as a large mass.

(Example of the third embodiment)
Next, examples (including comparative examples) of the third embodiment of the present invention will be described.

(Experimental example 11)
In Experimental Example 11, the same polyamide composition as in Example 1, that is, 85% nylon 66, 15% silicon, and about 5 cm of air bag waste containing silicon-coated polyamide as in Example 1. × 10cm, and using the shredded airbag waste, melting pot insertion process → ethylene glycol injection process → solution heating process → solution cooling process → vacuum drying recovery process / non-fluid stirring process .

  In Experimental Example 11, a large amount of ethylene glycol was charged into the melting pot 3, and the melting pot 3 was heated with a heating burner (not shown), so that 1/2 of the ethylene glycol charged into the melting pot 3 was reduced. When the concentration of nylon 66 in the ethylene glycol solution was 20%, the primary nylon 66 recovery rate was examined. As a result, the recovery rate of the primary nylon 66 of the nylon 66 at that time was 82%. Thus, even when a large amount of ethylene glycol was added to the dissolution vessel 3 to make the nylon 66 concentration of the ethylene glycol solution approximately 20%, the primary nylon 66 recovery rate of nylon 66 was high. .

(Experimental example 12)
In Experimental Example 12, 70% of the ethylene glycol charged in the melting pot 3 is distilled off by heating the melting pot 3 with a heating burner (not shown) using the same airbag waste as in Experimental Example 11. When the concentration of nylon 66 in the ethylene glycol solution reached 35%, the primary nylon 66 recovery rate of nylon 66 was examined and found to be 47%. In this way, when ethylene glycol is added to the dissolution vessel 3 in a large amount, and a little more ethylene glycol is distilled off to make the concentration of nylon 66 in the ethylene glycol solution 35%, the primary nylon 66 of nylon 66 is removed. The recovery rate was low.

  Since the present invention is a recycling method in which polyamide is purified from a silicon-coated air bag, which has been difficult in the past, and is recovered, products such as fibers and films, which have been difficult in the past as well as molded products, are regenerated products. It can be widely used as a raw material.

DESCRIPTION OF SYMBOLS 1 Polyamide collection | recovery apparatus 2 Net-shaped container 3 Melting pot 3a Melting pot lid 4 Reflux condenser 5 Cooling tank 6 On-off valve 11 Polyamide collection apparatus 12 Supply tank 13 Filtration tank 14 Vacuum tank 15 Flux condenser 16 Recovery tank 17 Vacuum pump 18 Gear pump 19 Nozzle plate 21 Solvent recovery condenser 22 Solvent recovery tank 23a Condenser switching section 23b Condenser switching section

Claims (3)

A solution heating step in which a polyamide composition containing a polyamide combined or mixed with a substance insoluble in ethylene glycol is heated together with ethylene glycol at a temperature of 180 ° C. or more, and separated from the substance insoluble in polyamide and ethylene glycol;
A polyamide recovery step for recovering the polyamide separated from the substance insoluble in ethylene glycol by the solution heating step;
Recycling method of polyamide composition having The polyamide recovery step includes
A solution cooling step of cooling an ethylene glycol solution of polyamide having a concentration of 10% to 30% of the polyamide separated from the substance insoluble in ethylene glycol to 130 ° C. or less;
A vacuum drying recovery step of recovering the polyamide by vacuum drying a non-fluid consisting of ethylene glycol and polyamide solidified by cooling in the solution cooling step at 130 ° C. or less, and distilling off ethylene glycol. A method for recycling the polyamide composition according to 1. The polyamide recovery step includes
A vacuum chamber discharge step in which an ethylene glycol solution of polyamide separated from a substance insoluble in ethylene glycol is passed through a nozzle plate in which holes having a diameter of 0.1 mm to 1.0 mm are formed, and the inside is discharged to a vacuum chamber having a vacuum; ,
2. A method for recycling a polyamide composition according to claim 1, further comprising a vaporization and recovery step of recovering the polyamide by evaporating ethylene glycol of the ethylene glycol solution of the polyamide released in the vacuum chamber release step in a vacuum chamber.

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